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How should i charge 3 lithium ion batteries?
PWM lithium-ion chargerhow to charge two 18650 3.7v batteries?How to charge 18650 lithium ion cells together?Multi-cell li-ion chargerAt what point in the charge cycle do lithium ion batteries draw the most current?Is it safe and efficient to charge a Li-Ion cell from mixed alkaline cells?Lithium Ion prolonged lifespanIf I have two 18650 Li-ion batteries with different capacities, can I charge them using the same circuit?1S or 2S li-ion battery charging design for ESP32/Nextion device
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$begingroup$
I'm new to battery charging and I was wondering. What is the best way to charge and manage 3 18650 cell batteries? The load is about an amp and I have a 3.7 amp power supply to charge them. I'd like to be able to charge the batteries and also power my device.
I plan on using the batteries in series, i'm aware that i need to use a 3S balance board, and a constant current converter to charge them, but is it safe to draw power from the batteries while charging? and where do i connect the load to?
Thanks for your response!
batteries battery-charging lithium-ion
asked 9 hours ago
RamsomRamsom
233 bronze badges
New contributor
Ramsom is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
add a comment |
$begingroup$
I'm new to battery charging and I was wondering. What is the best way to charge and manage 3 18650 cell batteries? The load is about an amp and I have a 3.7 amp power supply to charge them. I'd like to be able to charge the batteries and also power my device.
I plan on using the batteries in series, i'm aware that i need to use a 3S balance board, and a constant current converter to charge them, but is it safe to draw power from the batteries while charging? and where do i connect the load to?
Thanks for your response!
batteries battery-charging lithium-ion
asked 9 hours ago
RamsomRamsom
233 bronze badges
New contributor
Ramsom is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
1
$begingroup$
I have a 3.7 amp power supply to charge them You don't mention the output voltage of that power supply which is a quite important parameter. I really suggest that you browse the Internet and see how others do this. There is plenty of information to be found usually related to RC cars etc. It is safer to understand what you're doing rather than rely on "connect A to B" instructions as there you can easily make a mistake and ruin your day.
$endgroup$
– Bimpelrekkie
8 hours ago
add a comment |
$begingroup$
I'm new to battery charging and I was wondering. What is the best way to charge and manage 3 18650 cell batteries? The load is about an amp and I have a 3.7 amp power supply to charge them. I'd like to be able to charge the batteries and also power my device.
I plan on using the batteries in series, i'm aware that i need to use a 3S balance board, and a constant current converter to charge them, but is it safe to draw power from the batteries while charging? and where do i connect the load to?
Thanks for your response!
batteries battery-charging lithium-ion
asked 9 hours ago
RamsomRamsom
233 bronze badges
New contributor
Ramsom is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
I'm new to battery charging and I was wondering. What is the best way to charge and manage 3 18650 cell batteries? The load is about an amp and I have a 3.7 amp power supply to charge them. I'd like to be able to charge the batteries and also power my device.
I plan on using the batteries in series, i'm aware that i need to use a 3S balance board, and a constant current converter to charge them, but is it safe to draw power from the batteries while charging? and where do i connect the load to?
Thanks for your response!
batteries battery-charging lithium-ion
batteries battery-charging lithium-ion
asked 9 hours ago
RamsomRamsom
233 bronze badges
New contributor
Ramsom is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 9 hours ago
RamsomRamsom
233 bronze badges
New contributor
Ramsom is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 9 hours ago
RamsomRamsom
233 bronze badges
New contributor
Ramsom is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 9 hours ago
RamsomRamsom
233 bronze badges
asked 9 hours ago
RamsomRamsom
233 bronze badges
233 bronze badges
New contributor
Ramsom is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Ramsom is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
1
$begingroup$
I have a 3.7 amp power supply to charge them You don't mention the output voltage of that power supply which is a quite important parameter. I really suggest that you browse the Internet and see how others do this. There is plenty of information to be found usually related to RC cars etc. It is safer to understand what you're doing rather than rely on "connect A to B" instructions as there you can easily make a mistake and ruin your day.
$endgroup$
– Bimpelrekkie
8 hours ago
add a comment |
1
$begingroup$
I have a 3.7 amp power supply to charge them You don't mention the output voltage of that power supply which is a quite important parameter. I really suggest that you browse the Internet and see how others do this. There is plenty of information to be found usually related to RC cars etc. It is safer to understand what you're doing rather than rely on "connect A to B" instructions as there you can easily make a mistake and ruin your day.
$endgroup$
– Bimpelrekkie
8 hours ago
1
1
$begingroup$
I have a 3.7 amp power supply to charge them You don't mention the output voltage of that power supply which is a quite important parameter. I really suggest that you browse the Internet and see how others do this. There is plenty of information to be found usually related to RC cars etc. It is safer to understand what you're doing rather than rely on "connect A to B" instructions as there you can easily make a mistake and ruin your day.
$endgroup$
– Bimpelrekkie
8 hours ago
$begingroup$
I have a 3.7 amp power supply to charge them You don't mention the output voltage of that power supply which is a quite important parameter. I really suggest that you browse the Internet and see how others do this. There is plenty of information to be found usually related to RC cars etc. It is safer to understand what you're doing rather than rely on "connect A to B" instructions as there you can easily make a mistake and ruin your day.
$endgroup$
– Bimpelrekkie
8 hours ago
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
i'm aware that i need to use a 3S balance board, and a constant
current converter to charge them
You need more than just a current source. The charger must limit the voltage to 4.20V per cell (12.6V total), and (if you want to get more than 80% charge into the battery) then continuously reduce the current at that voltage until it reaches ~1/10 the set charge rate, then shut off. If you are using a basic CC/CV (Constant Current / Constant Voltage) converter then it probably won't shut off, so set the 'float' voltage to 4.15V per cell.
To prevent over-discharge you should have a cutoff circuit that disconnects the load when the battery reaches 3.0V per cell (9V total). If the battery gets very low (<3V/cell) it should be charged at a lower rate until the voltage reaches ~3.7V per cell (11.1V total).
is it safe to draw power from the batteries while charging?
Yes, but the battery won't charge if the load current is higher than the charging current. Assuming you have 3.7A at >12.6V available and the load only takes 1A, there is 2.7A free for charging. However the charge current must not exceed the battery's rating, which might be eg. 1.5A. So you could set the charge current to 2.5A, but if the load is turned off then the battery would get 2.5A which is too much. Therefore the charger has to monitor battery current separately from the load, or charge at 1.5A which will only get 0.5A into the battery while the load is on.
and where do i connect the load to?
To the battery through the 'balance' board.
Alternatively you could power the load from the power supply when it is on, and charge the battery at the same time with its output isolated from the load. This has the advantage that the battery can be charged at full rate even when the load is on, but the circuit is more complex.
If the load can work at slightly higher than 12.6V then a simple diode switch-over circuit might suffice. Details are important though. With the charger and load sharing a common ground the charger must monitor current in the battery positive lead, not negative, otherwise load current would upset the charger circuit.
Li-ion batteries can explode if they are overcharged, so don't charge unattended until you are sure that the circuit is working properly.
answered 7 hours ago
Bruce AbbottBruce Abbott
28.3k1 gold badge24 silver badges39 bronze badges
$endgroup$
$begingroup$
Hello, each of the batteries have their own protection circuits, so I think the overcharge and overdischarge problems are solved. Thanks for your helpful response!
$endgroup$
– Ramsom
4 hours ago
$begingroup$
@Ramsom careful with relying on those in series, because say an overcharge circuit trips and the battery ends up disconnected on one end - the protection circuit might expect say up to a 5v charge voltage, but if it remains in series with other cells that aren't fully charged, it could end up recieving much closer to your full charger voltage (i.e. say you charging the entire pack with a 15v charger, relying on the cells to turn off individually once charged - if the first cell charges to 4.2v and shuts off, while the others are at 3.5v you will have (15-3.5*2)= 8v on the first cell)
$endgroup$
– user2813274
1 hour ago
$begingroup$
@Ramsom For something that can catch fire, you might consider having the battery's protection circuits be the backups to your own. Two things that have to fail before your house/garage/whatever burns down.
$endgroup$
– Wayne Conrad
9 mins ago
add a comment |
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$begingroup$
i'm aware that i need to use a 3S balance board, and a constant
current converter to charge them
You need more than just a current source. The charger must limit the voltage to 4.20V per cell (12.6V total), and (if you want to get more than 80% charge into the battery) then continuously reduce the current at that voltage until it reaches ~1/10 the set charge rate, then shut off. If you are using a basic CC/CV (Constant Current / Constant Voltage) converter then it probably won't shut off, so set the 'float' voltage to 4.15V per cell.
To prevent over-discharge you should have a cutoff circuit that disconnects the load when the battery reaches 3.0V per cell (9V total). If the battery gets very low (<3V/cell) it should be charged at a lower rate until the voltage reaches ~3.7V per cell (11.1V total).
is it safe to draw power from the batteries while charging?
Yes, but the battery won't charge if the load current is higher than the charging current. Assuming you have 3.7A at >12.6V available and the load only takes 1A, there is 2.7A free for charging. However the charge current must not exceed the battery's rating, which might be eg. 1.5A. So you could set the charge current to 2.5A, but if the load is turned off then the battery would get 2.5A which is too much. Therefore the charger has to monitor battery current separately from the load, or charge at 1.5A which will only get 0.5A into the battery while the load is on.
and where do i connect the load to?
To the battery through the 'balance' board.
Alternatively you could power the load from the power supply when it is on, and charge the battery at the same time with its output isolated from the load. This has the advantage that the battery can be charged at full rate even when the load is on, but the circuit is more complex.
If the load can work at slightly higher than 12.6V then a simple diode switch-over circuit might suffice. Details are important though. With the charger and load sharing a common ground the charger must monitor current in the battery positive lead, not negative, otherwise load current would upset the charger circuit.
Li-ion batteries can explode if they are overcharged, so don't charge unattended until you are sure that the circuit is working properly.
answered 7 hours ago
Bruce AbbottBruce Abbott
28.3k1 gold badge24 silver badges39 bronze badges
$endgroup$
$begingroup$
Hello, each of the batteries have their own protection circuits, so I think the overcharge and overdischarge problems are solved. Thanks for your helpful response!
$endgroup$
– Ramsom
4 hours ago
$begingroup$
@Ramsom careful with relying on those in series, because say an overcharge circuit trips and the battery ends up disconnected on one end - the protection circuit might expect say up to a 5v charge voltage, but if it remains in series with other cells that aren't fully charged, it could end up recieving much closer to your full charger voltage (i.e. say you charging the entire pack with a 15v charger, relying on the cells to turn off individually once charged - if the first cell charges to 4.2v and shuts off, while the others are at 3.5v you will have (15-3.5*2)= 8v on the first cell)
$endgroup$
– user2813274
1 hour ago
$begingroup$
@Ramsom For something that can catch fire, you might consider having the battery's protection circuits be the backups to your own. Two things that have to fail before your house/garage/whatever burns down.
$endgroup$
– Wayne Conrad
9 mins ago
add a comment |
$begingroup$
i'm aware that i need to use a 3S balance board, and a constant
current converter to charge them
You need more than just a current source. The charger must limit the voltage to 4.20V per cell (12.6V total), and (if you want to get more than 80% charge into the battery) then continuously reduce the current at that voltage until it reaches ~1/10 the set charge rate, then shut off. If you are using a basic CC/CV (Constant Current / Constant Voltage) converter then it probably won't shut off, so set the 'float' voltage to 4.15V per cell.
To prevent over-discharge you should have a cutoff circuit that disconnects the load when the battery reaches 3.0V per cell (9V total). If the battery gets very low (<3V/cell) it should be charged at a lower rate until the voltage reaches ~3.7V per cell (11.1V total).
is it safe to draw power from the batteries while charging?
Yes, but the battery won't charge if the load current is higher than the charging current. Assuming you have 3.7A at >12.6V available and the load only takes 1A, there is 2.7A free for charging. However the charge current must not exceed the battery's rating, which might be eg. 1.5A. So you could set the charge current to 2.5A, but if the load is turned off then the battery would get 2.5A which is too much. Therefore the charger has to monitor battery current separately from the load, or charge at 1.5A which will only get 0.5A into the battery while the load is on.
and where do i connect the load to?
To the battery through the 'balance' board.
Alternatively you could power the load from the power supply when it is on, and charge the battery at the same time with its output isolated from the load. This has the advantage that the battery can be charged at full rate even when the load is on, but the circuit is more complex.
If the load can work at slightly higher than 12.6V then a simple diode switch-over circuit might suffice. Details are important though. With the charger and load sharing a common ground the charger must monitor current in the battery positive lead, not negative, otherwise load current would upset the charger circuit.
Li-ion batteries can explode if they are overcharged, so don't charge unattended until you are sure that the circuit is working properly.
answered 7 hours ago
Bruce AbbottBruce Abbott
28.3k1 gold badge24 silver badges39 bronze badges
$endgroup$
$begingroup$
Hello, each of the batteries have their own protection circuits, so I think the overcharge and overdischarge problems are solved. Thanks for your helpful response!
$endgroup$
– Ramsom
4 hours ago
$begingroup$
@Ramsom careful with relying on those in series, because say an overcharge circuit trips and the battery ends up disconnected on one end - the protection circuit might expect say up to a 5v charge voltage, but if it remains in series with other cells that aren't fully charged, it could end up recieving much closer to your full charger voltage (i.e. say you charging the entire pack with a 15v charger, relying on the cells to turn off individually once charged - if the first cell charges to 4.2v and shuts off, while the others are at 3.5v you will have (15-3.5*2)= 8v on the first cell)
$endgroup$
– user2813274
1 hour ago
$begingroup$
@Ramsom For something that can catch fire, you might consider having the battery's protection circuits be the backups to your own. Two things that have to fail before your house/garage/whatever burns down.
$endgroup$
– Wayne Conrad
9 mins ago
add a comment |
$begingroup$
i'm aware that i need to use a 3S balance board, and a constant
current converter to charge them
You need more than just a current source. The charger must limit the voltage to 4.20V per cell (12.6V total), and (if you want to get more than 80% charge into the battery) then continuously reduce the current at that voltage until it reaches ~1/10 the set charge rate, then shut off. If you are using a basic CC/CV (Constant Current / Constant Voltage) converter then it probably won't shut off, so set the 'float' voltage to 4.15V per cell.
To prevent over-discharge you should have a cutoff circuit that disconnects the load when the battery reaches 3.0V per cell (9V total). If the battery gets very low (<3V/cell) it should be charged at a lower rate until the voltage reaches ~3.7V per cell (11.1V total).
is it safe to draw power from the batteries while charging?
Yes, but the battery won't charge if the load current is higher than the charging current. Assuming you have 3.7A at >12.6V available and the load only takes 1A, there is 2.7A free for charging. However the charge current must not exceed the battery's rating, which might be eg. 1.5A. So you could set the charge current to 2.5A, but if the load is turned off then the battery would get 2.5A which is too much. Therefore the charger has to monitor battery current separately from the load, or charge at 1.5A which will only get 0.5A into the battery while the load is on.
and where do i connect the load to?
To the battery through the 'balance' board.
Alternatively you could power the load from the power supply when it is on, and charge the battery at the same time with its output isolated from the load. This has the advantage that the battery can be charged at full rate even when the load is on, but the circuit is more complex.
If the load can work at slightly higher than 12.6V then a simple diode switch-over circuit might suffice. Details are important though. With the charger and load sharing a common ground the charger must monitor current in the battery positive lead, not negative, otherwise load current would upset the charger circuit.
Li-ion batteries can explode if they are overcharged, so don't charge unattended until you are sure that the circuit is working properly.
answered 7 hours ago
Bruce AbbottBruce Abbott
28.3k1 gold badge24 silver badges39 bronze badges
$endgroup$
i'm aware that i need to use a 3S balance board, and a constant
current converter to charge them
You need more than just a current source. The charger must limit the voltage to 4.20V per cell (12.6V total), and (if you want to get more than 80% charge into the battery) then continuously reduce the current at that voltage until it reaches ~1/10 the set charge rate, then shut off. If you are using a basic CC/CV (Constant Current / Constant Voltage) converter then it probably won't shut off, so set the 'float' voltage to 4.15V per cell.
To prevent over-discharge you should have a cutoff circuit that disconnects the load when the battery reaches 3.0V per cell (9V total). If the battery gets very low (<3V/cell) it should be charged at a lower rate until the voltage reaches ~3.7V per cell (11.1V total).
is it safe to draw power from the batteries while charging?
Yes, but the battery won't charge if the load current is higher than the charging current. Assuming you have 3.7A at >12.6V available and the load only takes 1A, there is 2.7A free for charging. However the charge current must not exceed the battery's rating, which might be eg. 1.5A. So you could set the charge current to 2.5A, but if the load is turned off then the battery would get 2.5A which is too much. Therefore the charger has to monitor battery current separately from the load, or charge at 1.5A which will only get 0.5A into the battery while the load is on.
and where do i connect the load to?
To the battery through the 'balance' board.
Alternatively you could power the load from the power supply when it is on, and charge the battery at the same time with its output isolated from the load. This has the advantage that the battery can be charged at full rate even when the load is on, but the circuit is more complex.
If the load can work at slightly higher than 12.6V then a simple diode switch-over circuit might suffice. Details are important though. With the charger and load sharing a common ground the charger must monitor current in the battery positive lead, not negative, otherwise load current would upset the charger circuit.
Li-ion batteries can explode if they are overcharged, so don't charge unattended until you are sure that the circuit is working properly.
answered 7 hours ago
Bruce AbbottBruce Abbott
28.3k1 gold badge24 silver badges39 bronze badges
answered 7 hours ago
Bruce AbbottBruce Abbott
28.3k1 gold badge24 silver badges39 bronze badges
answered 7 hours ago
Bruce AbbottBruce Abbott
28.3k1 gold badge24 silver badges39 bronze badges
answered 7 hours ago
Bruce AbbottBruce Abbott
28.3k1 gold badge24 silver badges39 bronze badges
28.3k1 gold badge24 silver badges39 bronze badges
$begingroup$
Hello, each of the batteries have their own protection circuits, so I think the overcharge and overdischarge problems are solved. Thanks for your helpful response!
$endgroup$
– Ramsom
4 hours ago
$begingroup$
@Ramsom careful with relying on those in series, because say an overcharge circuit trips and the battery ends up disconnected on one end - the protection circuit might expect say up to a 5v charge voltage, but if it remains in series with other cells that aren't fully charged, it could end up recieving much closer to your full charger voltage (i.e. say you charging the entire pack with a 15v charger, relying on the cells to turn off individually once charged - if the first cell charges to 4.2v and shuts off, while the others are at 3.5v you will have (15-3.5*2)= 8v on the first cell)
$endgroup$
– user2813274
1 hour ago
$begingroup$
@Ramsom For something that can catch fire, you might consider having the battery's protection circuits be the backups to your own. Two things that have to fail before your house/garage/whatever burns down.
$endgroup$
– Wayne Conrad
9 mins ago
add a comment |
$begingroup$
Hello, each of the batteries have their own protection circuits, so I think the overcharge and overdischarge problems are solved. Thanks for your helpful response!
$endgroup$
– Ramsom
4 hours ago
$begingroup$
@Ramsom careful with relying on those in series, because say an overcharge circuit trips and the battery ends up disconnected on one end - the protection circuit might expect say up to a 5v charge voltage, but if it remains in series with other cells that aren't fully charged, it could end up recieving much closer to your full charger voltage (i.e. say you charging the entire pack with a 15v charger, relying on the cells to turn off individually once charged - if the first cell charges to 4.2v and shuts off, while the others are at 3.5v you will have (15-3.5*2)= 8v on the first cell)
$endgroup$
– user2813274
1 hour ago
$begingroup$
@Ramsom For something that can catch fire, you might consider having the battery's protection circuits be the backups to your own. Two things that have to fail before your house/garage/whatever burns down.
$endgroup$
– Wayne Conrad
9 mins ago
$begingroup$
Hello, each of the batteries have their own protection circuits, so I think the overcharge and overdischarge problems are solved. Thanks for your helpful response!
$endgroup$
– Ramsom
4 hours ago
$begingroup$
Hello, each of the batteries have their own protection circuits, so I think the overcharge and overdischarge problems are solved. Thanks for your helpful response!
$endgroup$
– Ramsom
4 hours ago
$begingroup$
@Ramsom careful with relying on those in series, because say an overcharge circuit trips and the battery ends up disconnected on one end - the protection circuit might expect say up to a 5v charge voltage, but if it remains in series with other cells that aren't fully charged, it could end up recieving much closer to your full charger voltage (i.e. say you charging the entire pack with a 15v charger, relying on the cells to turn off individually once charged - if the first cell charges to 4.2v and shuts off, while the others are at 3.5v you will have (15-3.5*2)= 8v on the first cell)
$endgroup$
– user2813274
1 hour ago
$begingroup$
@Ramsom careful with relying on those in series, because say an overcharge circuit trips and the battery ends up disconnected on one end - the protection circuit might expect say up to a 5v charge voltage, but if it remains in series with other cells that aren't fully charged, it could end up recieving much closer to your full charger voltage (i.e. say you charging the entire pack with a 15v charger, relying on the cells to turn off individually once charged - if the first cell charges to 4.2v and shuts off, while the others are at 3.5v you will have (15-3.5*2)= 8v on the first cell)
$endgroup$
– user2813274
1 hour ago
$begingroup$
@Ramsom For something that can catch fire, you might consider having the battery's protection circuits be the backups to your own. Two things that have to fail before your house/garage/whatever burns down.
$endgroup$
– Wayne Conrad
9 mins ago
$begingroup$
@Ramsom For something that can catch fire, you might consider having the battery's protection circuits be the backups to your own. Two things that have to fail before your house/garage/whatever burns down.
$endgroup$
– Wayne Conrad
9 mins ago
add a comment |
Ramsom is a new contributor. Be nice, and check out our Code of Conduct.
Ramsom is a new contributor. Be nice, and check out our Code of Conduct.
Ramsom is a new contributor. Be nice, and check out our Code of Conduct.
Ramsom is a new contributor. Be nice, and check out our Code of Conduct.
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$begingroup$
I have a 3.7 amp power supply to charge them You don't mention the output voltage of that power supply which is a quite important parameter. I really suggest that you browse the Internet and see how others do this. There is plenty of information to be found usually related to RC cars etc. It is safer to understand what you're doing rather than rely on "connect A to B" instructions as there you can easily make a mistake and ruin your day.
$endgroup$
– Bimpelrekkie
8 hours ago